ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

2aSC3. Locus equations as phonetic descriptors of consonantal place of
articulation.

This experiment tested whether locus equation coefficients, slope, and y
intercept could serve as indices of place of articulation for obstruents sharing
the same place of articulation across different manner classes. A previous study
[C. A. Fowler, Percept. Psychophys. 55, 597--610 (1994)] reported that locus
equations provided poor information for place because the mean slope for /d/
(0.47) was found to be statistically different than the mean slope for /z/
(0.42) across ten speakers. Locus equations from 22 speakers were derived from
CV/t/ words with initial voiced oral stop /d/, voiceless aspirated stop /t[sup
h]/, nasal stop /n/, voice fricative /z/, and voiceless fricative /s/ preceding
ten vowel contexts. Post-hoc tests revealed /d/=/z/=/n/ for slope means. Slopes
for /d/ and /t[sup h]/ were also equivalent when F2 onset measurement points
were corrected to account for aspiration. Scatterplots of slopes x y intercepts
revealed three nonoverlapping and distinct clusters of coordinates when the
coronal group (/d, t, n, z, s/) was plotted versus labials and velars. A
discriminant analysis using slope and y intercept successfully categorized all
coronals as alveolars with 87.1% accuracy. The collective results support the
contention that locus equations can serve as effective descriptors of consonant
place of articulation across manner classes. [Work supported by NIH.]